fix GeneratedColumnPlaceHolderTransformAction header (pingcap#8951) (p…

…ingcap#8954)

close pingcap#8787

dbms/src/DataStreams/GeneratedColumnPlaceholderBlockInputStream.h

@@ -84,7 +84,7 @@ class GeneratedColumnPlaceholderBlockInputStream : public IProfilingBlockInputSt
             if (insert_data)
                 column = data_type->createColumnConstWithDefaultValue(block.rows());
             else
-                column = data_type->createColumn();
+                column = data_type->createColumnConstWithDefaultValue(0);
             block.insert(col_index, ColumnWithTypeAndName{column, data_type, col_name});
         }
     }

tests/fullstack-test/mpp/generated_column.test

@@ -0,0 +1,29 @@
+# Copyright 2024 PingCAP, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Preparation.
+mysql> drop table if exists test.t
+mysql> create table test.t (col int null, __col int as (col) virtual);
+mysql> alter table test.t set tiflash replica 1
+mysql> insert into test.t (col) values (1);
+
+func> wait_table test t
+
+mysql> use test; set @@tidb_allow_mpp=0; set @@tidb_allow_batch_cop=2; set @@tidb_isolation_read_engines='tiflash'; select * from t order by col limit 10;
+col	__col
+1	1
+
+mysql> use test; set @@tidb_allow_mpp=1; set @@tidb_enforce_mpp=1; set @@tidb_isolation_read_engines='tiflash'; select * from t order by col limit 10;
+col	__col
+1	1